Current Population Survey (CPS) Basic Monthly Data at the NBER

The CPS is the U.S. Government's monthly survey of unemployment and labor force
participation. The BLS maintains a CPS Home Page
with a great deal of information about the survey and access to downloads of
recent data.
The CPS basic monthly files contain information on labor force status but
do not contain the full income and demographic data contained in the March supplements,
nor do they contain usual hours or wages except for the households in the outgoing
rotation group.

A housing unit in the CPS is interviewed for four consecutive months and
then dropped out of the sample for the next eight months and is brought
back in the following four months. So, in any given month, one-eighth
of the housing units are interviewed for the first month. When the
system has been in operation for a full year, four of the eight rotation
groups for any month will have been in the survey for the same month, one
year ago.
Matching information and Stata .do files from
NBER Working Paper t0247
by B. Madrian and L. J. Lefgren are available for March-to-March Annual Demographic
File matches but can be modified for use in matching CPS Basic Monthly Data.
Technical Paper
such as 66 and 63 contains more information about Design and Methodology.

To check your ability to uncompress these files, download the small files
compress.Z or compress.zip.
They give an example of how to read in .Z and .zip ASCII files into SAS for UNIX without
decompressing the files.

To download files in Internet Explorer, right click on them and select "Save Target As...".
If the pdf documents appear to be all blank pages, get the latest Acrobat
Reader at www.abobe.com.

All data files follow the naming convention
cpsbYYMM where YY is year and MM is month.
The 1976-1988 data documentation calls every group of six Characters a Word. To convert Words
and Characters into plain characters multiply the number of previous Words by six and add the
number of character positions within the designated Word. That will give the location of the
first character of the variable of interest. For example, State is in
Word 3, Characters 5-6. 2 previous words * 6 = 12 + 5 = 17 = the starting location
of State.

The file layouts are the basically the same for the following periods: 1976-1988, 1989-1993, 1994-1997, and 1998-2004.
SAS, SPSS, and Stata data definition statement files for 1989 on
are available.
Merge.sas gives an example of how to read in multiple months and years
and merge them into a single datafile.

From 1976-1993 variables and record lengths can vary by record type as described in the documentation.

Weekly hours/earnings are not included in these files from 1976-1983.
From 1976-1978, these variables are available in the May Extracts.
From 1979 on, these variables are available in the Merged Outgoing Rotation Groups.

NOTE: Usually, the documentation from January applies to an entire year. Execptions are 1984-1985 and 1994-1995. The
January 1984 documentation is used through to June 1985. The July 1985 documentation applies to the remainder
of 1985. For 1994-1995, the January 1994 documentation is used through August 1995. The September 1995 documentation
serves for the rest of the year.

** Usually, the documentation from January applies to an entire year. Execptions are 1984-1985 and 1994-1995. The
January 1984 documentation is used through to June 1985. The July 1985 documentation applies to the remainder
of 1985. For 1994-1995, the January 1994 documentation is used through August 1995. The September 1995 documentation
serves for the rest of the year.

To report problems or if you have comments or suggestions, e-mail jroth@nber.org